The article examines different models for pricing American call options on dividend-paying stocks using Australian data. Three models are compared: Roll, Geske, and Whaley's approach, which adjusts for dividends and early exercise; and two simpler models. The study also looks at the impact of delays between option and stock trades on pricing accuracy. Results show that all models underprice options compared to market prices and have biases related to stock volatility, option maturity, and strike price. The Roll-Geske-Whaley model performs best among the three.